The joint I'm working on is the lowest one in the house for hot water. Would it be too weird to install another tee and elbow further down the line, maybe behind the vanity, that would drop down from the hot horizontal supply line, thus becoming the lowest hot water joint -- it may be useful for future use, too. I could cap it off. Would that help with the joint I'm working on?

Another solution may be to lower the hot supply line to the lavatory sink. Right now, I've got my hot and cold stubouts at 18" above the floor. I could lower the hot stubout below the horizontal supply line in the wall. They wouldn't look uniform, but not sure that matters. That way, I could use the hot angle stop to drain the whole house hot water if I ever needed to.

Any thoughts on any of this?

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: Having the shower uncapped would not help with the problem, since the water would have to fill the pipe to that level which is well above the joint you are working on. You must have the open pipe lower than the joint you are soldering.

: : In a Terry Love message in 1998, he said "Remember, that there must be an open faucet when soldering. If not, the last joint soldered will leak." I'm having that problem with a hot water supply line going to a shower faucet mixer. All other stubouts are capped. I've tried to inset a T into the horizontal supply line several times and it keeps leaking. There doesn't appear to be water in the pipes when I get started and I've even put in a little bread to make sure. But after heating the fitting for a short time, I'll start getting drips out of the bottom of the T fitting.

: : I've opened the mixer valve all the way to where hot water would come out of the showerhead if there was hot water. The tub spout is capped.

: : I have not drained the cold water lines since those are leak-free. Does that matter -- could it be the water coming in from the cold side of the mixer when I get started? Any thoughts on how to get a leak-free connection with the T? I could uncap the hot water lavatory stubout (about 5' away) if steam build-up is a problem.